Is gender only culture?

“Gender is a social construction.” This statement, often attributed to feminist theory and post-structuralist philosophy, has become a recurring slogan in public debates on gender identity. But it is also a simplification that, taken literally, risks obscuring decades of scientific research. Is gender identity really just the product of the culture in which we grow up? Or are there biological factors that influence it? And if the answer involves both, how do they interact?

The constructionist thesis

The idea that gender is entirely a social construction has roots in the feminist philosophy of the second half of the twentieth century. Simone de Beauvoir, in “The Second Sex” (1949), wrote the famous line: “One is not born, but rather becomes, a woman.” This formulation, born as a critique of the biological determinism that justified the subordination of women, was the starting point for a long intellectual tradition.

Judith Butler and gender performativity

The most influential contribution to the constructionist theory of gender is that of Judith Butler, an American philosopher, in the book “Gender Trouble” (1990) [1]. Butler argues that gender is not a natural given but a performative act: not something one “is,” but something one “does” through the daily repetition of gestures, behaviors, and social norms. In this perspective, the categories “man” and “woman” are not innate biological facts, but the result of cultural practices that present themselves as natural.

Butler’s analysis has had an enormous influence in gender studies and queer theory, providing conceptual tools for understanding how gender norms are constructed, imposed, and contested. However, Butler’s thinking primarily concerns gender roles and social norms associated with the masculine and feminine — not necessarily the inner sense of belonging to a gender, which in the scientific literature is defined as gender identity [3].

The contribution of anthropological studies

Anthropology has provided important data in support of the cultural variability of gender norms. The roles associated with the masculine and feminine change significantly across different cultures: what is considered “masculine” in one society may be “feminine” in another. The very existence of nonbinary gender identities in many cultures around the world (see below) demonstrates that the Western binary system is not a biological universal.

These data demonstrate that gender expressions and gender roles are strongly influenced by culture. But they also demonstrate something else: that in very different societies, with profoundly different gender norms, there are still people whose gender identity does not correspond to the sex assigned at birth. If gender were exclusively a cultural construction, we would expect that in cultures with more flexible norms these experiences would disappear. They do not.

The biological evidence

Parallel to the development of constructionist theories, biological research has accumulated a growing body of data on the role of genes, hormones, and brain structures in the development of gender identity. These data do not contradict the importance of culture, but they indicate that gender is not only culture.

Genetics and twin studies

Twin studies represent one of the most robust tools for distinguishing the contribution of genes and environment. A systematic review of the twin literature, published in Behavior Genetics in 2025, analyzed eight studies yielding heritability estimates ranging from 0.10 to 0.81, with seven of eight studies providing evidence supporting a genetic component [10]. If gender identity were exclusively cultural, monozygotic twins (who share 100% of their DNA) should not show greater concordance than dizygotic twins. Instead, concordance is systematically higher in identical twins [10].

Prenatal hormones and brain differentiation

Research on brain differentiation, synthesized by Swaab and Garcia-Falgueras (2009), has shown that the fetal brain goes through critical periods during which steroid hormones influence the formation of neural circuits related to gender identity [7]. Genital differentiation occurs in the first trimester of pregnancy, while brain differentiation continues in the second and third trimesters. This temporal gap could explain why, in some cases, the direction of brain development diverges from that of genital development [7].

People with congenital adrenal hyperplasia (CAH), exposed to elevated androgen levels during fetal development, show significantly higher rates of gender incongruence compared to the general population — a finding difficult to explain in exclusively cultural terms [3].

Epigenetics

A study published in Frontiers in Neuroscience in 2021 conducted an epigenomic analysis comparing the DNA methylation profiles of transgender and cisgender people before hormone treatment, finding significant differences in sites associated with genes involved in central nervous system development [12]. Epigenetics may represent the mechanism through which biological and environmental factors interact in determining gender identity.

For a comprehensive treatment of the biological evidence, see the article on the biological bases of gender identity.

The case of David Reimer

One of the most dramatic — and most illuminating — experiments on the nature-versus-culture question in gender identity was not conducted in a laboratory, but on the life of a real person.

In 1966, Bruce Reimer, a Canadian infant with XY chromosomes, suffered irreparable damage to his penis during a circumcision. Psychologist John Money, a proponent of the theory that gender identity was entirely determined by upbringing, advised the parents to raise Bruce as a girl. The child was subjected to surgery, renamed Brenda, and raised as a girl.

Money presented the case as a success of his theory, publishing it widely as proof that gender identity is malleable by the environment. For years, the “John/Joan case” was cited in textbooks as a demonstration of gender plasticity.

The reality was different. Diamond and Sigmundson published a follow-up in 1997 that revealed the actual outcome [2]: “Brenda” had never identified as female. From childhood, she had rejected the toys, clothes, and behaviors associated with the female gender. At the age of 14, after learning the truth about his own history, he chose to live as male, taking the name David. Despite having been raised as female for over a decade, in a family environment that actively supported that identity, his inner sense of belonging to a gender had not changed [2].

The Reimer case does not prove that culture is irrelevant. It does prove, however, that upbringing alone is not sufficient to determine gender identity, and that attempting to override that inner sense has devastating consequences.

Confirmation from similar cases

Meyer-Bahlburg (2005) analyzed a broader case series of 46,XY individuals raised as female due to conditions such as penile agenesis, cloacal exstrophy, or penile ablation [8]. The results showed that a significant percentage of these individuals — ranging from 25% to 63% depending on the condition — developed a male gender identity despite female assignment and upbringing. These data, from clinical contexts independent of the Reimer case, confirm that gender identity is not entirely moldable by the environment [8].

Gender identity beyond the binary: cross-cultural evidence

If gender were exclusively a product of modern Western culture, we would not find nonbinary gender identities in societies that are geographically and historically distant. Instead, we find them everywhere.

The hijra of India

The hijra are people assigned male at birth who identify with a female gender or with a third gender. Their existence is documented in texts dating back thousands of years in the Indian subcontinent. Anthropologist Serena Nanda, in her ethnographic study “Neither Man nor Woman” (1999), documented how the hijra occupy a recognized social role in Indian culture, with specific ritual functions [5]. In India, a third gender has been legally recognized since 2014.

The fa’afafine of Samoa

In Samoa, fa’afafine are people assigned male at birth who assume roles and behaviors traditionally associated with the feminine. Vasey and Bartlett (2007) studied the fa’afafine in research published in Perspectives in Biology and Medicine, finding that these individuals show cross-gender behaviors from childhood, in a cultural context that not only tolerates but socially integrates them [4]. The existence of fa’afafine in a society with gender norms very different from Western ones suggests that the incongruence between assigned sex and gender identity is not a Western cultural artifact, but a phenomenon that transcends cultural boundaries [4].

Two-Spirit in Native North American cultures

The term Two-Spirit is an umbrella term adopted in 1990 to describe people in Native North American cultures who occupy gender roles outside the binary. Before European colonization, at least 155 Native North American tribes formally recognized multiple gender identities. These individuals often held specific spiritual and social roles within their communities.

The sworn virgins of Albania

In the mountainous regions of Albania and Kosovo, the burrnesha (literally “sworn virgins”) are people assigned female at birth who, through a public oath, assume a male social identity. This practice, documented since the fifteenth century, demonstrates how some cultures have institutionalized the passage between gender roles, implicitly recognizing that birth assignment is not always definitive.

What these examples tell us

The existence of nonbinary gender identities in such diverse cultures — in terms of era, geography, religion, and social organization — indicates that variance in gender identity is not the product of a specific cultural configuration. Culture determines the forms this variance takes (hijra, fa’afafine, Two-Spirit, transgender person), but not the variance itself.

The interactionist model: neither only nature, nor only culture

The opposition “nature versus culture” is a false dichotomy. Scientific research over the past thirty years has led the academic community toward an interactionist model, in which biological and environmental factors do not operate independently but influence each other.

What is biological, what is cultural

It is useful to distinguish among different aspects of gender [13]:

• Gender identity — the inner sense of being a man, a woman, or a different gender — shows a significant biological component, as evidenced by twin studies, prenatal hormone effects, and neuroscientific research [3][10].
• Gender roles — the behaviors, activities, and social expectations associated with the masculine and feminine — are largely cultural constructions. Janet Shibley Hyde (2005), in a meta-analysis of 46 meta-analyses published in the American Psychologist, demonstrated that psychological differences between men and women are in most cases small or negligible, contradicting the idea of deep innate differences between the sexes [13].
• Gender expression — the way a person outwardly manifests their gender through clothing, behavior, and appearance — is strongly influenced by cultural context.

The brain as a mosaic

Joel et al. (2015), in a study published in the Proceedings of the National Academy of Sciences, analyzed brain scans of over 1,400 people, demonstrating that the human brain cannot be neatly classified as “male” or “female” [6]. Most individuals present a mosaic of traits, some more common in males and others in females. This finding suggests that brain biology is more complex than a simple dichotomy, and that individual differences exceed group differences [6].

This does not mean that the brain is irrelevant to gender identity. It means that the relationship between brain structure, biology, and identity is more nuanced than simplistic models — both purely biological and purely cultural — suggest.

The scientific consensus

The Endocrine Society, in its 2017 guidelines, states that “considerable scientific evidence has established a durable biological element underlying gender identity” and that “the matter transcends simple social choice” [9]. This position does not deny the importance of culture, but establishes that biology plays a role that cannot be reduced to zero.

The World Health Organization, with the adoption of the ICD-11, reclassified gender incongruence from the chapter on mental disorders to that on conditions related to sexual health [11]. This decision reflects the consensus that gender identity is not the result of a mental pathology or of external cultural influence, but an aspect of human diversity with biological bases.

Polderman et al. (2018), in the most comprehensive available review, conclude that gender identity “likely reflects a complex interplay of biological, environmental, and cultural factors” [3]. None of these factors is sufficient on its own.

Why the answer matters

The question “is gender only culture?” is not merely academic. The answers have direct consequences for people’s lives.

If gender identity were exclusively cultural, one could hypothesize modifying it through education or therapy — a reasoning that has historically justified so-called “conversion therapies.” Scientific evidence shows that these attempts do not work and cause significant harm, as recognized by the major international health organizations [9].

If gender identity were exclusively biological, social and cultural contexts would be irrelevant to the well-being of transgender people. Evidence shows the opposite: social acceptance, family support, and access to care are determining factors for the mental and physical health of trans people.

A synthesis

Gender identity is not only culture. It is not only biology either. It is the result of a complex interaction among genetic predispositions, prenatal hormonal environment, epigenetic mechanisms, and social and cultural context [3][7][10][12]. Constructionist theories have provided indispensable tools for dismantling rigid gender roles and oppressive norms. The biological sciences have demonstrated that gender identity has roots that upbringing alone can neither create nor erase [2][8].

The case of David Reimer shows what happens when one attempts to impose a gender identity from outside [2]. Nonbinary gender identities documented in dozens of cultures around the world demonstrate that gender variance is not a specific product of contemporary Western culture [4][5]. Twin studies confirm a significant heritable component [10]. And neurobiological research reveals mechanisms that operate before birth, before any cultural influence [7].

Science does not support the position that gender is “only culture,” just as it does not support the position that it is “only biology.” Reality, as often happens, is more complex than either simplification. And in this complexity lies the key to understanding — and respecting — the diversity of human experience.